This invention relates to the preparation of trans-decahydronaphthalene compounds, which are known or are homologs of conventional 7a.beta.-alkyl-perhydroindan-5-one derivatives. They are utilized for the total synthesis of pharmacologically active D-homo steroids, including 19-nor-D-homo-testosterone, D-homo-19-norandrost-4-en-3,17a-dione, 3-oxo-D-homo-21,24-dinor-17a.alpha.-chol-4-en-23,17a-lacton, 17a.alpha.-tert-butoxy-D-homoostr-4-en-3-one.
Compounds of Formula I can be made by condensing octahydronaphthalene derivatives of Formula II with a vinyl ketone of the formula XCOCH.dbd.CH.sub.2 and hydrogenating the resulting compounds of Formula VII ##STR6## wherein X, Y, and R.sub.1 are as above.
However, the vinyl ketone is not selectively added to the double bond, especially if X is lower alkyl. Also, hydrogenation of the compounds of Formula VII does not take place stereospecifically, so that also undesired isomeric compounds are formed in addition to the compounds of Formula I.
To avoid these disadvantages, processes have been suggested for the preparation of compounds of Formula I which make it possible to effect selective alkylation and hydrogenation, but which are rather expensive because of the large number of steps in the synthesis. See, DOS's (German Unexamined Laid-Open Applications) 1,950,012; published Apr. 9, 1970 2,130,053; published Dec. 14, 1972 2,160,066; published June 7, 1973 2,228,473; published Dec. 20, 1973 2,228,474 published Dec. 20, 1973 and 2,228,475 published Dec. 20, 1973.
The process of this invention provides for the synthesis of compounds of Formula I in high yields and high purity in a simple manner.